Hydrogenation and hydrogen transfer reactions using transition metal complexes are important methods for producing optically active compounds. It is known that prochiral ketones are reacted in the presence of a transition metal catalyst by using a secondary alcohol, formic acid, hydrogen, or the like as a hydrogen source, in general.

Since a transition metal catalyst having a reducing function also has an oxidizing function, oxidation of the produced secondary alcohol occurs in some cases, causing decrease in optical purity of the product.

Since these reactions proceed under a neutral or basic condition, a method in which an acid such as hydrochloric acid is added or the like is employed for stopping these reactions.